What are the complications associated with egg retrieval in In Vitro Fertilization (IVF)?

Complications Associated with Egg Retrieval in IVF

The most serious complication of egg retrieval is ovarian hyperstimulation syndrome (OHSS), which can cause capillary leak syndrome, thromboembolism, renal failure, and in rare cases, death. 1, 2, 3

Major Complications

Ovarian Hyperstimulation Syndrome (OHSS)

OHSS is the most serious iatrogenic complication of ovarian stimulation, occurring in 5.3-14.3 per 1,000 IVF cycles depending on the era and protocols used. 4, 5, 6

• Severe OHSS can result in hemoconcentration, hypovolemia, thromboembolism, and death, making it a life-threatening condition requiring immediate recognition. 5
• A documented case exists of sudden death on the operating table during oocyte retrieval due to acute massive pulmonary edema from OHSS, demonstrating the potential for catastrophic outcomes even in young, healthy donors without apparent risk factors. 3
• The syndrome presents in two distinct temporal patterns: early OHSS (3-7 days post-hCG) and late OHSS (12-17 days post-hCG), each with different risk factors and no overlap between presentations. 7

Risk Factors for OHSS

Early OHSS is predicted by the number of oocytes retrieved (particularly >30 oocytes) and estradiol concentration on the day hCG is administered. 7, 6

• Retrieving more than 13-15 oocytes increases OHSS risk without improving pregnancy rates, making this a critical threshold for monitoring. 1
• Patients with polycystic ovarian disease are at highest risk (adjusted risk ratio 2.61), requiring lower starting doses of gonadotropins and careful monitoring. 5, 6
• Late OHSS is induced by rising hCG from early pregnancy and is associated with multiple gestation (2-3 gestational sacs), not with oocyte number or estradiol levels. 7
• Underlying thrombophilias increase the risk of severe OHSS, requiring prophylactic anticoagulation with low molecular weight heparin starting with ovarian stimulation. 2

Pregnancy-Related Complications

OHSS is associated with increased risk of adverse pregnancy outcomes, including preterm delivery and low birth weight in both singleton and twin pregnancies. 6

• In singleton pregnancies, OHSS increases the risk of low birth weight (adjusted risk ratio 1.29) and preterm delivery (adjusted risk ratio 1.32). 6
• In twin pregnancies, OHSS increases the risk of second-trimester loss (adjusted risk ratio 1.81), low birth weight (adjusted risk ratio 1.06), and preterm delivery (adjusted risk ratio 1.16). 6

Ectopic Pregnancy

The risk of ectopic pregnancy increases up to 20-fold with the number of embryos transferred, representing another serious complication of the IVF process. 4

• Ectopic pregnancy rates are elevated after transfer of two versus one embryo, regardless of developmental stage or freezing status. 4
• The rate of ectopic pregnancy is higher after transfer of non-top-quality embryos, adding another dimension to embryo selection considerations. 4

Prevention Strategies

Accurate prediction using ultrasound and estradiol assays with strict prevention by withholding hCG or cryopreserving all embryos has major impact on OHSS occurrence. 5

• For patients with polycystic ovarian disease, use small doses with slow-start HMG protocols, tailoring dosage according to ovarian response. 5
• Luteal phase supplementation should use progesterone rather than hCG in cycles where estradiol exceeds 2500 ng/L or when more than 10 oocytes are retrieved. 5
• Anticoagulation should be interrupted 24-36 hours before oocyte retrieval and resumed afterward in patients with antiphospholipid antibodies or known thrombophilias. 2

Common Pitfalls

The main determining factor in OHSS development is ovarian predisposition rather than protocol selection, meaning some patients remain at risk despite optimal management. 5

• GnRH agonist protocols, despite initial expectations, are associated with higher prevalence of OHSS compared to other suppression methods. 5, 6
• Pregnancy following fresh embryo transfer is a modifiable risk factor (adjusted risk ratio 3.12), making freeze-all strategies protective in high-risk patients. 6
• Fixed-schedule IVF cycles without detailed monitoring are not associated with increased OHSS incidence, suggesting that over-monitoring may not always improve safety. 5